JPH08297042A - Liquid level detector - Google Patents

Abstract

PURPOSE: To detect the liquid level accurately while maintaining the performance of pressure gauge for a long term by providing a lead-out channel with a branch pipe and fixing a pressure gauge to the branch pipe through a noncorrosive fluid layer thereby suppressing damage or deterioration of the pressure gauge. CONSTITUTION: A lead-out channel 1 for feeding oil L to the outside is provided with a pressure gauge 2 for detecting the pressure of the oil L, and a branch path 3 for containing a gas hermetically having a part 4 communicated with the lead-out channel 1. The pressure gauge 2 is set to detect the pressure of oil L by detecting the pressure of gas contained hermetically in the branch path 3. A converter 5 converts the detected pressure into the liquid level in a tank T and transfers the information of liquid level to a liquid level indicator 6 located at a remote place B. Since the residual quantity of oil L in the tank T is presented digitally on the indicator 6 at a remote place B, liquid level in the tank T can be confirmed on the indicator 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a liquid storage tank having an outlet for letting out an internal liquid to the outside, and a pressure gauge capable of detecting the pressure of the liquid is provided in the outlet. Regarding a liquid level detection device provided with a conversion means for converting the liquid level in the tank based on the pressure detected by the pressure gauge, for example, a liquid level of a heavy oil tank or the like provided for heating a vinyl house in a field The present invention relates to a liquid level detection device for monitoring liquid.

[0002]

2. Description of the Related Art Conventionally, as this type of liquid level detecting device,
There was one that was configured so that the liquid level in the tank could be directly viewed, such as by providing a communication pipe on the side of the liquid storage tank so that the liquid level can be seen through, but always monitor the liquid level. Is not realistic, and the liquid level height of the tank cannot be visually confirmed at a remote place. Furthermore, in order to constantly monitor the liquid level at a remote location, a sensor for detecting the liquid level and a conversion device that enables communication to a remote location must be individually provided for each tank. When processing each tank,
Usually, it is necessary to install the sensor inside the tank, and the larger the tank, the more time-consuming it takes to process it, and when converting to an electrical signal at the liquid level, it depends on the type of liquid in the tank. However, the structure tends to be complicated, such as requiring an explosion-proof structure, and the sensor itself is expensive. Therefore, as a configuration that can monitor the liquid level height in each tank without performing processing for each tank, a pressure gauge, for example, provided with a diaphragm in the outlet passage through which the internal liquid flows out from the tank is provided. To make a series
A configuration has been proposed in which the pressure of the liquid applied to the diaphragm is converted into a liquid surface height signal and can be output (for example, Japanese Utility Model Laid-Open No. 4-127524).

[0003]

According to the pressure detecting device described above, there is an advantage that the height of the liquid level in the tank can be known without processing the tank, but the pressure gauge is Since the pressure gauge is in direct contact with the liquid, there is a problem in that the pressure gauge is likely to be corroded or deteriorated. So, for example,
When a pressure gauge provided with a diaphragm is provided in the discharge path of the heavy oil tank, the result is that the diaphragm is corroded by hydrogen sulfide, which is an impurity mixed in the heavy oil, and the durability of the diaphragm is shortened. Was becoming. Further, when the liquid is replenished into the tank or when the liquid in the tank is suddenly discharged, a sudden pressure change occurs in the liquid, an excessive load is applied to the pressure gauge, and However, the pressure gauge may be deteriorated or damaged. Even if the liquid is liquid fuel such as heavy oil or kerosene or water, or the pressure gauge is of a diaphragm type or a semiconductor type pressure sensor, the risk of deterioration or damage is the same. It is conceivable, and further improvement was required.

Therefore, an object of the present invention is to improve the above-mentioned drawbacks and to provide a pressure detecting device in which the pressure gauge is provided in the lead-out path while stabilizing the performance.

[0005]

A characteristic configuration of the present invention for achieving the above object is to detect a pressure of the liquid in a discharge passage for discharging the liquid to an outside in a tank storing the liquid inside. In a liquid level detecting device provided with a gauge and converting means for converting the pressure detected by the pressure gauge to the liquid level height in the tank, a branch pipe is attached to the outlet passage, and the branch pipe is non-corrosive. The pressure gauge is attached via a fluid layer, the non-corrosive fluid layer may be a closed gas layer or a liquid layer, and the non-corrosive fluid layer is a closed gas layer or an incompressible liquid. It may be composed of a layer and a closed gas layer, and its function and effect are as follows.

[0006]

In other words, since the pressure gauge detects the pressure of the closed gas layer, it does not come into contact with the liquid flowing out of the tank and is less susceptible to deterioration such as corrosion due to the direct contact of the liquid. If the non-corrosive fluid layer is a closed gas layer, it has a function of buffering the pressure fluctuation of the liquid due to the abrupt fluctuation of the liquid level in the tank and transmitting it to the pressure gauge. There is little possibility that a sudden pressure fluctuation will be transmitted. Therefore, the liquid level height in the tank can be detected by converting the pressure to the liquid level height in the tank by the conversion means. Furthermore, if the non-corrosive fluid layer is composed of a closed gas layer, a non-compressible liquid layer, and a closed gas layer, the liquid in the tank and the vapor of the corrosive component contained in the liquid are sealed. It is possible to block the diffusion movement in the gas layer to reach the pressure gauge, and further reduce the risk of deterioration or damage of the pressure gauge.

[0007]

Therefore, it is possible to prevent the pressure gauge from being damaged or deteriorated, and to accurately detect the liquid level in the tank while keeping the performance of the pressure gauge high for a long period of time. Is now possible. Also, since the liquid level can be known remotely, such as converting the liquid level to an electrical signal and transferring it to a remote location, the liquid level of multiple tanks can be concentrated. This is advantageous when managing.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the liquid level detection device according to the present invention includes an oil L for supplying a combustor H for heating a vinyl house A.
In the tank T that stores the oil inside, a pressure gauge 2 that can detect the pressure of the oil L is provided in a lead-out path 1 that causes the oil L to flow to the outside, and a branch path 3 that stores gas in an airtight state is provided inside. A communication portion 4 that communicates the outlet passage 1 is provided in the branch passage 3, and the pressure gauge 2 is provided so that the pressure of the sealed gas in the branch passage 3 can be detected to detect the pressure of the oil L.
A converter 5 for converting the liquid level in the tank T based on the pressure detected by the pressure gauge 2 is provided, and liquid level information obtained by the converter 5 is provided at a remote location (indoor) B. The liquid level height is transferred to the display device 6.

The tank T has a height of about 1 to 2 m, has an oil supply port T1 for refueling into the tank T and an exhaust air vent T2 in the upper part, and a drain discharge port T3 for discharging the drain in the lower part.
And a lead-out port T4 for refueling the combustor H. As shown in FIGS. 1 and 2, a lead-out pipe 1a having a diameter of about 20 mm is communicatively connected to the lead-out port T4 via a valve V1, and a branch pipe 1b is provided on the lead-out pipe 1a to have a height of about 5 to 6 cm.
The branch path 3 of is constructed. Main pipe side 1 of the branch pipe 1b
A fuel supply portion of the combustor H is communicatively connected to c. Also,
A pressure gauge 2 is arranged on the branch side 1d of the branch pipe 1b via a closed air layer 3a. The pressure gauge 2 detects a pressure by strain of a diaphragm, and a pressure detection unit 2a provided with a pressure sensor capable of detecting the strain as a change in electrical resistance, and a change in the electrical resistance as an electrical signal. And an output unit 2b for outputting, and a pressure detection unit 2a
Is housed in the closed air layer 3a, and is configured to transmit the pressure in the closed air layer 3a to the output portion 2b. The pressure change transmitted to the output unit 2b is transmitted to the conversion device 5, and the conversion device 5 converts the pressure information into liquid level height information and outputs the information.
Since it is displayed on the display device 6 that digitally displays the remaining amount of oil L in the tank T, it is possible to know the liquid level in the tank T just by looking at the display device 6 at the remote place B. is there. That is, when pressure is applied to the branch passage according to the height of the liquid surface in the tank T, the pressure gauge 2 can detect the pressure and output the liquid surface height based on the pressure. Therefore, the liquid level height can be detected without contacting the pressure gauge 2 with oil, and the durability of the pressure gauge 2 can be increased. In addition, even if the liquid level changes abruptly, the air pressure in the closed air layer 3a does not change abruptly.

FIG. 3 shows the relationship between the sensor output E (unit V) indicating the pressure in the closed air layer 3a and the liquid level height h1 (unit cm) in the tank T. However, the reference point for h1 = 0 is the liquid surface height at which the closed air layer 8a has begun to be formed (see FIG. 1). The pressure gauge used is of a type that detects a difference from the atmospheric pressure with a differential pressure gauge, and the output (reference point) in the atmospheric pressure is 1.0V. From FIG. 3, it can be seen that the sensor output E and the liquid level height h1 are in a proportional relationship, and the liquid level height h1 can be detected by measuring the pressure in the closed air layer 3a.

Another embodiment will be described below. The branch road 3
May be configured as shown in FIG. That is,
A U-shaped pipe 3A is communicatively connected to a branch side 1d of the branch pipe 1b, an incompressible liquid layer 3b is provided on the U-shaped pipe 3A, and an incompressible liquid layer 3b to a closed air layer is provided on the U-tube tip side. 3c
A non-corrosive fluid layer is composed of three layers by providing a pressure gauge between the two layers. With such a configuration, it is possible to block the vapor of the oil L from reaching the pressure gauge 2, so that the deterioration of the pressure gauge 2 can be further suppressed. In addition, the branch path 3
Indicates a portion branched from a main pipe line whether it is simply formed from the branch pipe 1b or provided with the U-shaped pipe 3A, and these are collectively referred to as a branch pipe.

Further, instead of the oil L, other ones such as an aqueous solution of a chemical may be used, and these are collectively referred to as a liquid, and the liquid may be used in various ways other than the supply to the combustor H. Available in form. The non-corrosive fluid layer may be a closed gas layer made of an inert gas such as nitrogen in addition to the closed air layer, which are collectively referred to as a closed gas layer. Further, it may be a liquid layer made of silicone oil or the like, and in short, it may be made of gas or liquid that does not corrode the pressure gauge 2. For example, when the specific gravity of the liquid layer is lower than the specific gravity of the non-corrosive fluid layer, as shown in FIG. 5, a downward branch pipe 1e is provided to form a branch passage 3 to form the pressure gauge 2 and the liquid L. A non-corrosive fluid layer composed of a liquid layer 3d and a closed gas layer 3e can be interposed between them. Further, in the present invention, what is referred to as the outlet path is not limited to the outlet pipe 1a, but may be the drain outlet T3,
In short, it is only necessary that the pipeline communicates with the inside of the tank, and the oil supply pipe and the drain discharge port are collectively referred to as the outlet passage 1. Further, in order to provide the pressure gauge 2 in the oil supply pipe, it may be provided in the vicinity of the combustion device H instead of being provided in the vicinity of the tank T, and its arrangement position does not matter. That is, the configuration shown in FIG. 6 may be used. In FIG. 6, since the liquid level detection device is inside the vinyl house, it is advantageous in terms of weather resistance and is easy to manage when switching and using a plurality of tanks. In addition, various types of non-volatile oils are used, and in short, the non-compressible liquid layer 3b that blocks the vapor of the liquid such as the oil L from reaching the detection portion of the pressure gauge 2 may be used. Good. Furthermore, as the pressure gauge 2, the conversion device 5, the display device 6, and the like, known ones can be used as appropriate, and for example, the pressure gauge 2 that includes the capacitance type detection unit 2a may be used. Further, the conversion device 5 may convert an input of an electric signal of pressure information into an optical signal output of the liquid level. The conversion device 5 is collectively referred to as conversion means.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a schematic view showing a liquid level detection device of the present invention.

[Fig.2] Enlarged view of essential parts of liquid level detector

FIG. 3 is a graph showing the relationship between the liquid level and the detected pressure.

FIG. 4 is a schematic view showing another embodiment.

FIG. 5 is a schematic view showing another embodiment.

FIG. 6 is a schematic view showing another embodiment.

[Explanation of symbols]

 L liquid T tank 1 outlet path 2 pressure gauge 3 branch path 4 communication part 5 conversion means 3a closed gas layer 3b incompressible liquid layer 3c closed gas layer

Claims (4)

[Claims] 1. A pressure gauge (2) for detecting the pressure of the liquid (L) in a lead-out passage (1) for flowing the liquid (L) to the outside in a tank (T) which stores the liquid (L) therein. ) Is provided, and a conversion means (5) for converting the pressure detected by the pressure gauge (2) to the liquid level in the tank (T) is provided, and a branch pipe is provided in the outlet path. The pressure gauge (2) to which (3) is attached and the branch pipe (3) is provided with a non-corrosive fluid layer.
Liquid level detector with attached. 2. The non-corrosive fluid layer is a closed gas layer (3).
The liquid level detection device according to claim 1, wherein the liquid level detection devices are a) and (3c). 3. The liquid level detection device according to claim 1, wherein the non-corrosive fluid layer is a liquid layer (3d). 4. The non-corrosive fluid layer is a closed gas layer (3).
The liquid level detection device according to claim 1, wherein the liquid level detection device comprises a), an incompressible liquid layer (3b), and a closed gas layer (3c).